The avionic equipment items of an aircraft are made up of computers having the form of electronic cards installed in units or cabinets, connected to the electrical bundle of the aircraft. In practice, the electronic cards are installed by one of their edges into a slot provided for this purpose on a base installed in a unit. The back of the unit has a plurality of connectors disposed perpendicular to the base, so as to connect electrically the electronic cards installed on the base by an edge perpendicular to and immediately adjoining the edge installed in the slot of the base.
Usually, in a standard device comprising electronic cards, in order to remove an electronic card it is necessary to make sure to have cut off the electrical supply of the electronic card in order to avoid any damage to the electronic components before actuating the extractor in order to extract the card.
In avionic equipment items, there are modular equipment items wherein one of the sought objectives is to retain the availability of various avionic functions even when a given electronic card is removed. In concrete terms, it is a matter of being able to remove cards independently of one another and to see to it that the equipment is able to provide a given function despite the absence of one or more electronic cards.
In practice, in order to extract an electronic card, the operator sends out an extraction request on a central computer for a given card. The other cards then are reconfigured in order to be able to function without the chosen card and the power supply of the latter is cut off. A visual indicator tells the operator that he may extract the card.
Nonetheless, the risk remains that the operator will not remove the card on which the extraction request has been implemented, but another card. An erroneous extraction may damage the card in question. In addition, malfunctions of the system may occur since the system has not been reconfigured to operate without the card extracted by error.
The problem thus is to make extraction of the card subject to the modular preparation of the other electronic cards and to the cutoff of current thereto.
More generally, the problem therefore is to prevent incorrect or erroneous extractions of the electronic cards.
In order to be extracted, the cards are provided with extractors in the form of a lever making it possible to reduce an extraction force applied on the lever in order to contribute toward extracting the card.
In fact, the evolution of the number of components on the electronic cards led to the increase of the number of contacts between the cards and their connectors. The contact pressure on each of the cards is such that it is necessary to provide an extractor. In practice, an extraction may require a force ranging up to 350 N. It is understood that without the aid of an extractor, it is impossible to extract the card.